On Macs, if you are running the NetLogo application, the menubar is
located at the top of the screen. On other platforms, the menubar is
found at the top of the NetLogo window.

The functions available from the menus in the menubar are listed in
the following chart.

Chart: NetLogo Menus

File

New

Starts a new model.

Open

Opens any NetLogo model on your computer.

Models Library

A collection of
demonstration models.

Save

Save the current model.

Save As

Save the current model using a different name.

Save As Applet

Used to save a web page in HTML format that has your model embedded in it
as a Java "applet".

Print

Sends the contents of the currently showing tab to your printer.

Export World

Saves all variables and the current state of all turtles and patches to a file.

Export Plot

Saves the data in a plot to
a file.

Export All Plots

Saves the data in all the plots to a file.

Export Graphics

Save a picture of the graphics window to a file (in PNG format).

Export Output

Save the contents of the
output section of the command center to a file.

Import World

Load a file that was saved by Export World.

Quit

Exits NetLogo. (On Macs, this item is on the NetLogo menu instead.)

Edit

Cut

Cuts out or removes the
selected text and temporarily saves it to the clipboard.

Copy

Copies the selected text.

Paste

Places the clipboard text where cursor is currently located.

Delete

Deletes selected text.

Undo

Undo last text editing action you performed.

Find

Finds a word or sequence of characters within the Information, Procedures,
or Errors tab.

Find Again

Find the next occurrence of the word or sequence you last used Find with.

Shift Left /Shift Right

Used in the Procedures and Errors tabs to change the indentation
level of code.

Comment /Uncomment

Used in the Procedures and Errors tabs to add or remove semicolons
from code (semicolons are used in NetLogo code to indicate comments).

Tools

Halt

Stops all running code, including buttons and the command center. (Warning:
since the code is interrupted in the middle of whatever it was doing, you
may get unexpected results if you try to continue running the model without
first pressing "setup" to start the model run over.)

Globals Monitor

Displays the values of all global variables.

Turtle Monitor

Displays the values of all of the variables in a particular turtle. You can
can also edit the values of the turtle's variables and issue commands to the turtle. (You can also open a turtle monitor via the Graphics Window; see the Graphics Window section below.)

Patch Monitor

Displays the values of all of the variables in a particular patch. You can
can also edit the values of the patch's variables and issue commands to the patch. (You can also open a patch monitor via the Graphics Window; see the Graphics Window section below.)

At the top of NetLogo's main window are four tabs labeled
"Interface", "Information",
"Procedures", and "Errors". Only one tab at
a time can be visible, but you can switch between them by clicking on
the tabs at the top of the window.

Right below the row of tabs is a toolbar containing a row of
buttons. The buttons available vary from tab to tab.

The Interface tab is where you watch your model run. It also has
tools you can use to inspect and alter what's going on inside the
model.

When you first open NetLogo, the Interface tab is empty except for
the Graphics Window, where the turtles and patches appear, and the
Command Center, which allows you to issue NetLogo commands.

Interface Toolbar

The toolbar contains buttons that let you edit, delete, and create
items in the Interface tab (such as buttons and sliders).

The buttons in the toolbar are described below.

Working With Interface Elements

Selecting: To select an interface element, drag a rectangle
around it with your mouse. A gray border will appear around the
element to indicate that it is selected.

Selecting Multiple Items: You can select multiple interface
elements at the same time by including them in the rectangle you drag.
If multiple elements are selected, one of them is the "key" item,
which means that if you use the "Edit" or "Delete" buttons on the
Interface Toolbar, only the key item is affected. The key item is
indicated by a darker gray border than the other items.

Unselecting: To unselect all interface elements, click the
mouse on the white background of the Interface tab. To unselect an
individual element, control-click (Macintosh) or right-click (other
systems) the element and choose "Unselect" from the popup menu.

Editing: To change the characteristics of an interface
element, select the element, then press the "Edit" button
on the Interface Toolbar. You may also double click the element once
it is selected. A third way to edit an element is to control-click
(Macintosh) or right-click (other systems) it and choose
"Edit" from the popup menu. If you use this last method,
it is not necessary to select the element first.

Moving: Select the interface element, then drag it with your
mouse to its new location. If you hold down the shift key while
dragging, the element will move only straight up and down or straight
left and right.

Resizing: Select the interface element, then drag the
black "handles" in the selection border.

Deleting: Select the element or elements you want to delete,
then press the "Delete" button on the Interface Toolbar.
You may also delete an element by control-clicking (Macintosh) or
right-clicking (other systems) it and choosing "Delete"
from the popup menu. If you use this latter method, it is not
necessary to select the element first.

To learn more about the different kinds of interface elements,
refer to the chart below.

Chart: Interface Toolbar

Icon & Name

Description

Buttons can be either once-only buttons
or forever buttons. When you click on a once-button, it
executes its instructions once. The forever-button executes the
instructions over and over, until you click on the button again to
stop the action.

Sliders are global variables, which are accessible by
all agents. They are used in models as a quick way to change a
variable without having to recode the procedure every time.
Instead, the user moves the slider to a value and observe what
happens in the model.

Switches are a visual representation for a true/false variable. The
user is asked to set the variable to either on (true) or off (false)
by flipping the switch.

Choices let the user pick a value for a global variable from a list of choices,
presented in a drop down menu.

Monitors display the value of any expression. The expression could
be a variable, a complex expression, or a call to a reporter.
Monitors automatically update several times per second.

Plots are real-time graphs of data the model is generating.

A Text Box lets you create text labels in the Interface tab.

Graphics Window

The Graphics Window initially appears as a large black square on
the Interface tab. This is the graphical world of NetLogo's turtles
and patches.

Some NetLogo models let you interact with the turtles and patches
with your mouse by clicking and dragging in the Graphics Window.

The Graphics Window provides an easy way to open a turtle monitor
or patch monitor. Just control-click (Macintosh) or right-click
(other systems) on the turtle or patch you want to inspect, and choose
"inspect turtle ..." or "inspect patch ..."
from the popup menu. (Turtle and patch monitors can also be opened
from the Tools menu or by using the inspect command.)

There are a number of settings associated with the Graphics Window.
There are two ways of changing the settings: by using the control
strip along the top edge of the Graphics Window, or by editing the
Graphics Window, as described in the "Working With Interface
Elements" section above. (Or, pressing the
"More..." button in the control strip is an alternate and
quicker way.)

The controls in the control strip work as follows:

The three sets of black arrows let you change the size of the
world.

The slider lets you control how fast the model runs -- this
is valuable since some models run so fast that it's hard to see
what's going on.

The button with the arrowhead lets you turn turtle
"shapes" on and off. If shapes are off, turtles appear
as colored squares, instead of having special shapes. The squares
are less work for the computer to draw, so turning shapes off makes
models run faster.

The on-off switch lets you temporarily "freeze" the
display. The model keeps running, but the contents of the graphics
window don't change until you unfreeze it by flipping the switch
again. Most models run much faster when the graphics window is
frozen.

Here are the settings for the Graphics Window (accessible by
editing the Graphics Window, or by pressing the "More..."
button in the control strip):

To change the size of the Graphics Window adjust the "Patch
Size" setting, which is measured in pixels. This does not
change the number of patches, only how large the patches appear on the
screen. To change the number of patches, alter the "Screen Edge
X" and "Screen Edge Y" settings. (Note that
changing the numbers of patches requires rebuilding the NetLogo world;
you will lose all turtles and the values of all variables.)

The "Turtle Shapes" checkbox performs the same function
as the shapes button in the control strip, discussed above.

In most NetLogo models, turtles are visible at their exact
locations, and may vary in size. If you turn off the "Exact
Turtle Positions" checkbox, then:

Every turtle is drawn at the same size

Every turtle is drawn as if it were standing on the center of its patch

Only the top turtle on a patch is visible

This makes a model appear is it would have in earlier versions of
NetLogo, which did not support turtle sizes and exact turtle
positions. This checkbox does not change behavior of a model, only
its visual appearance.

Command Center

The Command Center allows you to issue commands directly, without
adding them to the model's procedures. (Commands are instructions you
give to turtles, patches, and the observer.) This is useful for
inspecting and manipulating agents on the fly.

You will notice there is a large display box, an agent popup menu
(O>), a "clear" button, and the history popup menu (with the little
black triangle). The top large display box temporarily stores all of
the commands that are entered into the Command Center. This area is
strictly for reference; commands cannot be accessed or changed from
this box. To clear this box, click "clear" in the top right corner.

The smaller text box, below the large box, is where commands are
entered. On the left of this box is the agent popup menu, and on
the right is the history popup menu.

The agent popup menu allows you to select either observer, turtles,
or patches. This is an easy way to assign an agent to a command and
it is the same as writing ask turtles [ ... ]. Note: a
quicker way to change between observer, turtles, and patches is to use
the tab key on your keyboard.

The history popup menu lists all of the commands entered that can
be accessed and used again. The up and down arrow keys on your
keyboard will retrieve that last command that was written.

Note that pressing the "clear" function clears only the large
display box and not the history. To clear the history section, choose
"clear history", found at the top of its popup menu.

This tab is the workspace where the code for the model is stored.
Commands you only want to use immediately go in the Command Center;
commands you want to save and use later, over and over again, are
found in the Procedures tab.

To determine if the code has any errors, press the
"Compile" button. If there are any syntax errors, the Errors
tab will come to the front of the screen and turn red. The code that
contains the error will be highlighted and a comment will appear in
the top box. Switching tabs also causes the code to be compiled and
any errors will be shown, so if you switch tabs, pressing the Compile
button first isn't necessary.

To find a fragment of code in the procedures, click on the
magnifying glass on the Procedures Toolbar. Then enter the text you
are looking for, and hit the "Find" button. The "Find
Again" button finds the next location of the word or fragment of code
throughout the procedure.

To find a particular procedure definition in your code,
use the "Procedures" popup menu in the Procedures Toolbar.
The menu lists all procedures in alphabetical order.

The "Shift Left", "Shift Right",
"Comment", and "Uncomment" items on the Edit
menu are used in the procedures tab to change the indentation level of
your code or add and remove semicolons, which mark comments, from
sections of code.

The Information tab provides an introduction to the model and an
explanation of how to use it, things to explore, possible extensions,
and NetLogo features. It is very helpful when you're first exploring
a model.

We recommend reading the Information tab before starting the model.
The Information tab explains what principle is being modeled and how
the model was created.

The Errors tab provides a place for errors to be highlighted and
brought to your attention. If there are any errors in your code, the
"Errors" tab will turn red and come to the front with an
explanation of what caused the error. When there are no errors,
the Tab is disabled.

Switching tabs, or pressing the "Compile" button in the
toolbar, causes your code to be checked for errors.